Respiratory mask has been widely used to provide continuous positive airway pressure (CPAP) to cure various respiratory diseases and SDB, such as obstructive sleep apnea (OSA), and/or provide other ventilation treatments such as non-invasive positive pressure ventilation (NIPPV).
The SDB treatment device normally includes a ventilator which transmits the positive pressure air to the user interface via an airway tube. The user interface may be a respiratory mask used on the nose or snout. Generally speaking, the respiratory mask includes a soft mask assembly in touch with the user's face and a rigid main frame. A chamber accommodating the nose or snout is formed by the main frame and the mask assembly consequently. The respiratory mask is fixed properly on the user's face by using a bandage device, which for instance binding across from the two sides of the user's face to the back or top of the user's head.
Since wearing the respiratory mask during sleep may cause asymmetric pressure on the user's face and may cause air leakage consequently, and to provide comfortable wearing experience, a forehead fixing device may also be set on the main frame. The forehead fixing device can provide a stable support via a support point between the respiratory mask and the user's forehead. As a result, the moving range of the mask is minimized and the wearing experience is improved.
However, different users have different facial features. In order to fit the heights of different users' foreheads, the forehead fixing device has to be adjustable. Though in the prior art, there already have some kinds of respiratory masks with adjustable forehead fixing devices, the structures are too complex and the manufacture processes are difficult and costly due to mass of parts. Therefore, an improvement of the respiratory mask is required.
Consequently, a new kind of respiratory mask and an adjustment assembly thereof are required to solve the problems mentioned above.